Cancer is one of the leading causes of death among humans. Although the mechanism for cancer development is not yet fully understood, it is believed that the metastasis of cancer cells contributes to the cause of death by cancer. In this case, the cancer cells proliferate, and spread to other parts of human body though the lymphatic system or vascular system. Such cancer cells are called circulating tumor cells (CTCs).
The detection of the circulating tumor cells has become one of the main topics in the field of cancer research. There are many different techniques for capturing and retrieving the circulating tumor cells, such as flow cytometry, cell filtration and immunomagnetic separation, in which the immunomagnetic separation technique is more commonly used. In the process of immunomagnetic separation, a plurality of magnetic beads are added into a sample containing multiple targeted cells. Each of the magnetic beads includes a plurality of antibodies that are able to bind with the targeted cells. After the targeted cells are bound with the antibodies of the magnetic beads, the magnetic beads are collected, achieving separation of the targeted cells from the sample. However, each of the magnetic beads might have multiple targeted cells bound thereon, which results in difficulty in subsequent analyses.